带有 Tiles 的 ListView 在 Flutter 中不起作用
ListView with Tiles not working in Flutter
为什么我的 ListView 没有显示预期的图块?
class DepartureCell extends StatelessWidget {
@override
Widget build(BuildContext context) {
return ListView.builder(
itemCount: 20,
itemBuilder: (BuildContext context, int index) {
return ListTile(
title: new Text("Test"),
onTap: () {},
);
}
);
}
}
错误说:
flutter: ══╡ EXCEPTION CAUGHT BY RENDERING LIBRARY ╞═════════════════════════════════════════════════════════
flutter: The following assertion was thrown during performResize():
flutter: Vertical viewport was given unbounded height.
flutter: Viewports expand in the scrolling direction to fill their container.In this case, a vertical
flutter: viewport was given an unlimited amount of vertical space in which to expand. This situation
flutter: typically happens when a scrollable widget is nested inside another scrollable widget.
flutter: If this widget is always nested in a scrollable widget there is no need to use a viewport because
flutter: there will always be enough vertical space for the children. In this case, consider using a Column
flutter: instead. Otherwise, consider using the "shrinkWrap" property (or a ShrinkWrappingViewport) to size
flutter: the height of the viewport to the sum of the heights of its children.
由于 unbound height
出现问题,我还尝试了以下操作:
代码也不起作用:
class DepartureCell extends StatelessWidget {
@override
Widget build(BuildContext context) {
return ListView.builder(
itemCount: 20,
itemBuilder: (BuildContext context, int index) {
return SizedBox(
width: double.infinity,
height: 40.0,
child: ListTile(
title: Text("Test"),
onTap: () {},
trailing: Text("Test"),
),
);
}
);
}
}
我怎样才能让它在 Flutter 中工作???
我也尝试过 Column
- 但同样的事情....不工作!
此处的列代码再次不起作用:
class DepartureCell extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Column(
children: <Widget>[
ListView.builder(
padding: EdgeInsets.all(0.0),
itemCount: 10,
itemBuilder: (BuildContext context, int position) {
return SizedBox(
width: double.infinity,
height: 40.0,
child:ListTile(
title: Text("Test"),
onTap: () {},
trailing: Text("Test"),
),
);
}
),
]
);
}
}
这是我找到的有效代码(见下文)...
不过,我确信它可以简化。但是怎么办??有什么建议吗??
这是完整的工作代码:
首先我在 main.dart 中调用 DepartueCell()...
import 'package:flutter/material.dart';
import './departures/cells/departure_cell.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
debugShowCheckedModeBanner: false,
home: Scaffold(
appBar: AppBar(
title: Text("CH Station Demo"),
),
body: DepartureCell()
),
);
}
}
然后我做剩下的....
import 'package:flutter/material.dart';
import './../../models/ch_departure.dart';
class DepartureCell extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Center(
child: ListView.builder(
padding: EdgeInsets.all(8.0),
itemCount: 10,
itemBuilder: (context, index) {
return Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
SizedBox(
width: double.infinity,
height: 50.0,
child: ListTile(
title: Text("Test"),
onTap: () {},
trailing: Text("Test2"),
),
)
],
);
}
),
);
}
}
谁能解释一下为什么我将所有内容打包到 Center 并将 Column 放入 ListView.builder 后它突然起作用了??
是否有更简单的解决方案??
我不知道你之前的代码是什么。如果您可以 post 您的早期代码,那么我可以向您解释异常。
这是代码的简化版本。
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
appBar: AppBar(
title: Text("CH Station Demo"),
),
body: DepartureCell()),
//home: TrackerApp(),
);
}
}
class DepartureCell extends StatelessWidget {
@override
Widget build(BuildContext context) {
return ListView.builder(
padding: EdgeInsets.all(8.0),
itemCount: 10,
itemBuilder: (context, index) {
return ListTile(
title: Text("Test"),
onTap: () {},
trailing: Text("Test2"),
);
});
}
}
我有同样的问题....在做了一些尝试后我发现当设备屏幕被锁定或关闭时会产生问题。
解锁屏幕和reload/rerun来自编辑器的应用程序可能会解决这个问题,就像它对我一样。
为什么我的 ListView 没有显示预期的图块?
class DepartureCell extends StatelessWidget {
@override
Widget build(BuildContext context) {
return ListView.builder(
itemCount: 20,
itemBuilder: (BuildContext context, int index) {
return ListTile(
title: new Text("Test"),
onTap: () {},
);
}
);
}
}
错误说:
flutter: ══╡ EXCEPTION CAUGHT BY RENDERING LIBRARY ╞═════════════════════════════════════════════════════════
flutter: The following assertion was thrown during performResize():
flutter: Vertical viewport was given unbounded height.
flutter: Viewports expand in the scrolling direction to fill their container.In this case, a vertical
flutter: viewport was given an unlimited amount of vertical space in which to expand. This situation
flutter: typically happens when a scrollable widget is nested inside another scrollable widget.
flutter: If this widget is always nested in a scrollable widget there is no need to use a viewport because
flutter: there will always be enough vertical space for the children. In this case, consider using a Column
flutter: instead. Otherwise, consider using the "shrinkWrap" property (or a ShrinkWrappingViewport) to size
flutter: the height of the viewport to the sum of the heights of its children.
由于 unbound height
出现问题,我还尝试了以下操作:
代码也不起作用:
class DepartureCell extends StatelessWidget {
@override
Widget build(BuildContext context) {
return ListView.builder(
itemCount: 20,
itemBuilder: (BuildContext context, int index) {
return SizedBox(
width: double.infinity,
height: 40.0,
child: ListTile(
title: Text("Test"),
onTap: () {},
trailing: Text("Test"),
),
);
}
);
}
}
我怎样才能让它在 Flutter 中工作???
我也尝试过 Column
- 但同样的事情....不工作!
此处的列代码再次不起作用:
class DepartureCell extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Column(
children: <Widget>[
ListView.builder(
padding: EdgeInsets.all(0.0),
itemCount: 10,
itemBuilder: (BuildContext context, int position) {
return SizedBox(
width: double.infinity,
height: 40.0,
child:ListTile(
title: Text("Test"),
onTap: () {},
trailing: Text("Test"),
),
);
}
),
]
);
}
}
这是我找到的有效代码(见下文)...
不过,我确信它可以简化。但是怎么办??有什么建议吗??
这是完整的工作代码:
首先我在 main.dart 中调用 DepartueCell()...
import 'package:flutter/material.dart';
import './departures/cells/departure_cell.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
debugShowCheckedModeBanner: false,
home: Scaffold(
appBar: AppBar(
title: Text("CH Station Demo"),
),
body: DepartureCell()
),
);
}
}
然后我做剩下的....
import 'package:flutter/material.dart';
import './../../models/ch_departure.dart';
class DepartureCell extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Center(
child: ListView.builder(
padding: EdgeInsets.all(8.0),
itemCount: 10,
itemBuilder: (context, index) {
return Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
SizedBox(
width: double.infinity,
height: 50.0,
child: ListTile(
title: Text("Test"),
onTap: () {},
trailing: Text("Test2"),
),
)
],
);
}
),
);
}
}
谁能解释一下为什么我将所有内容打包到 Center 并将 Column 放入 ListView.builder 后它突然起作用了??
是否有更简单的解决方案??
我不知道你之前的代码是什么。如果您可以 post 您的早期代码,那么我可以向您解释异常。
这是代码的简化版本。
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
appBar: AppBar(
title: Text("CH Station Demo"),
),
body: DepartureCell()),
//home: TrackerApp(),
);
}
}
class DepartureCell extends StatelessWidget {
@override
Widget build(BuildContext context) {
return ListView.builder(
padding: EdgeInsets.all(8.0),
itemCount: 10,
itemBuilder: (context, index) {
return ListTile(
title: Text("Test"),
onTap: () {},
trailing: Text("Test2"),
);
});
}
}
我有同样的问题....在做了一些尝试后我发现当设备屏幕被锁定或关闭时会产生问题。
解锁屏幕和reload/rerun来自编辑器的应用程序可能会解决这个问题,就像它对我一样。